Ten-speed transmission

ABSTRACT

A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/030,263, filed on Feb. 21, 2008, which is hereby incorporated in itsentirety herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches, planetary gear arrangements and fixed interconnections toachieve a plurality of gear ratios. The number and physical arrangementof the planetary gear sets, generally, are dictated by packaging, costand desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

In an aspect of the present invention, a transmission is provided havingan input member, an output member, four planetary gear sets, a pluralityof coupling members and a plurality of torque transmitting devices. Eachof the planetary gear sets includes first, second and third members. Afirst interconnecting member continuously interconnects the third memberof the first planetary gear set with the third member of the thirdplanetary gear set. A second interconnecting member continuouslyinterconnects the second member of the first planetary gear set with thethird member of the second planetary gear set. A third interconnectingmember continuously interconnects the first member of the secondplanetary gear set with the first member of the third planetary gearset. A fourth interconnecting member continuously interconnects thesecond member of the third planetary gear set with the second member ofthe fourth planetary gear set. Six torque transmitting mechanisms areselectively engageable to interconnect one of the first, second, andthird members with at least one other of the first members, secondmembers, third members and a stationary member. The torque transmittingmechanisms are selectively engageable in combinations of at least threeto establish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.

In another aspect of the present invention, the first of the six torquetransmitting mechanisms is selectively engageable to interconnect thesecond member of the first planetary gear set with the third member ofthe fourth planetary gear set.

In yet another aspect of the present invention, the second of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe first member of the fourth planetary gear set with the third memberof the fourth planetary gear set.

In yet another aspect of the present invention, the third of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the first member of the second planetary gear set andthe first member of the third planetary gear set with the first memberof the fourth planetary gear set.

In yet another aspect of the present invention, the fourth of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe first member of the first planetary gear set with the first memberof the fourth planetary gear set.

In yet another aspect of the present invention, the fifth of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the third member of the first planetary gear set and thethird member of the third planetary gear set with the stationary member.

In yet another aspect of the present invention, the sixth of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the second member of the first planetary gear set andthe third member of the second planetary gear set with the stationarymember.

In yet another aspect of the present invention, the third member of thefirst, third and fourth planetary gear sets and the first member ofsecond planetary gear set are sun gears, the second member of the first,second, third and fourth planetary gear sets are carrier members and thefirst member of the first, third and fourth planetary gear sets andthird member of second planetary gear set are ring gears.

In still another aspect of the present invention, the input member iscontinuously interconnected with at least one of the second member ofthe third planetary gear set and the second member of the fourthplanetary gear set and wherein the output member is continuouslyinterconnected the second member of the second planetary gear set.

In still another aspect of the present invention, the two of the torquetransmitting mechanisms are brakes and four of the torque transmittingmechanisms are clutches.

In still another aspect of the present invention, the stationary memberis a transmission housing.

Further objects, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic illustration of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that the embodiments of the tenspeed automatic transmission of the present invention have anarrangement of permanent mechanical connections between the elements ofthe four planetary gear sets. A second component or element of a firstplanetary gear set is permanently coupled to a third component orelement of the second planetary gear set. A third component or elementof the first planetary gear set is permanently coupled to a thirdcomponent or element of the third planetary gear set. A first componentor element of the second planetary gear set is permanently coupled tofirst component or element of the third planetary gear set. A secondcomponent or element of the third planetary gear set is permanentlycoupled to second component or element of the fourth planetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear are each represented by a node. Therefore, a single lever containsthree nodes: one for the sun gear, one for the planet gear carrier, andone for the ring gear. The relative length between the nodes of eachlever can be used to represent the ring-to-sun ratio of each respectivegear set. These lever ratios, in turn, are used to vary the gear ratiosof the transmission in order to achieve an appropriate ratios and ratioprogression. Mechanical couplings or interconnections between the nodesof the various planetary gear sets are illustrated by thin, horizontallines and torque transmitting devices such as clutches and brakes arepresented as interleaved fingers. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the second node 18B of the thirdplanetary gear set 18 and to second node 20B of the fourth planetarygear set 20. The output member 22 is coupled to the second node 16B ofthe second planetary gear set 16. The second node 14B of the firstplanetary gear set 14 is coupled to the third node 16C of the secondplanetary gear set 16. The third node 14C of the first planetary gearset 14 is coupled to the third node 18C of the third planetary gear set18. The first node 16A of the second planetary gear set 16 is coupled tothe first node 18A of the third planetary gear set 18. The second node18B of the third planetary gear set 18 is coupled to the second node 20Bof the fourth planetary gear set 20.

A first clutch 26 selectively connects the second node 14B of the firstplanetary gear set 14 with the third node 20C of the fourth planetarygear set 20. A second clutch 28 selectively connects the first node 20Aof the fourth planetary gear set 20 with the third node 20C of thefourth planetary gear set 20. A third clutch 30 selectively connectsfirst node 16A of the second planetary gear set 16 and the first node18A of the third planetary gear set 18 with the first node 20A of thefourth planetary gear set 20. A fourth clutch 32 selectively connectsthe first node 14A of the first planetary gear set 14 with the firstnode 20A of the fourth planetary gear set 20. A first brake 34selectively connects the third node 14C of the first planetary gear set14 to a stationary member or transmission housing 50. A second brake 36selectively connects the third node 16C of the second planetary gear set16 to a stationary member or transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14C, aring gear member 14A and a planet gear carrier member 14B that rotatablysupports a first set of planet gears 14D (only one of which is shown)and a second set of planet gears 14E (only one of which is shown). Thesun gear member 14C is connected for common rotation with a first shaftor interconnecting member 42 and a second shaft or interconnectingmember 44. The ring gear member 14A is connected for common rotationwith a third shaft or interconnecting member 46. The planet carriermember 14B is connected for common rotation with a fourth shaft orinterconnecting member 48 and a fifth shaft or interconnecting member52. The first set of planet gears 14D are each configured to intermeshwith both the sun gear member 14C and the second set of planet gears14E. The second set of planet gears 14E are each configured to intermeshwith both the ring gear member 14A and the first set of planet gears14D.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The sun gearmember 16A is connected for common rotation with a sixth shaft orinterconnecting member 54. The ring gear member 16C is connected forcommon rotation with the fifth shaft or interconnecting member 52. Theplanet carrier member 16B is connected for common rotation with outputshaft or member 22. The planet gears 16D are each configured tointermesh with both the sun gear member 16A and the ring gear member16C.

The planetary gear set 18 includes a sun gear member 18C, a ring gearmember 18A and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The sun gearmember 18C is connected for common rotation with second shaft orinterconnecting member 44. The ring gear member 18A is connected forcommon rotation with sixth shaft or interconnecting member 54 and with aseventh shaft or interconnecting member 56. The planet carrier member18B is connected for common rotation with input shaft or member 12 andwith an eighth shaft or interconnecting 58. The planet gears 18D areeach configured to intermesh with both the sun gear member 18C and thering gear member 18A.

The planetary gear set 20 includes a sun gear member 20C, a ring gearmember 20A and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The sun gearmember 20C is connected for common rotation with a ninth shaft orinterconnecting member 60. The ring gear member 20A is connected forcommon rotation with a tenth shaft or interconnecting member 62 and withan eleventh shaft or interconnecting member 64. The planet carriermember 20B is connected for common rotation with eighth shaft orinterconnecting member 58. The planet gears 20D are each configured tointermesh with both the sun gear member 20C and the ring gear member20A.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or clutches 26, 28, 30, 32 and brakes34 and 36 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the fourth shaft or interconnecting member 48 with the ninthshaft or interconnecting member 60. The second clutch 28 is selectivelyengageable to connect the ninth shaft or interconnecting member 60 withthe tenth shaft or interconnecting member 62. The third clutch 30 isselectively engageable to connect the seventh shaft or interconnectingmember 56 with the eleventh shaft or interconnecting member 64. Thefourth clutch 32 is selectively engageable to connect the third shaft orinterconnecting member 46 with the tenth shaft or interconnecting member62. The first brake 34 is selectively engageable to connect the firstshaft or interconnecting member 42 with the stationary element or thetransmission housing 50 in order to restrict the member 42 from rotatingrelative to the transmission housing 50. The second brake 36 isselectively engageable to connect the fifth shaft or interconnectingmember 52 with the stationary element or the transmission housing 50 inorder to restrict the member 52 from rotating relative to thetransmission housing 50.

Referring now to FIG. 2 and FIG. 3, the operation of the embodiment ofthe ten speed transmission 10 will be described. It will be appreciatedthat transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with quadruple overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,third clutch 30, fourth clutch 32, first brake 34 and second brake 36),as will be explained below. FIG. 3 is a truth table presenting thevarious combinations of torque-transmitting mechanisms that areactivated or engaged to achieve the various gear states. An “X” in thebox means that the particular clutch or brake is engaged to achieve thedesired gear state. An “O” represents that the particular torquetransmitting device (i.e. a brake or clutch) is on or active, but notcarrying torque. Actual numerical gear ratios of the various gear statesare also presented although it should be appreciated that thesenumerical values are exemplary only and that they may be adjusted oversignificant ranges to accommodate various applications and operationalcriteria of the transmission 10. An example of the gear ratios that maybe obtained using the embodiments of the present invention are alsoshown in FIG. 3. Of course, other gear ratios are achievable dependingon the gear diameter, gear teeth count and gear configuration selected.

To establish a reverse gear, the first clutch 26, fourth clutch 32 andsecond brake 36 are engaged or activated. The first clutch 26 connectsthe fourth shaft or interconnecting member 48 with the ninth shaft orinterconnecting member 60. The fourth clutch 32 connects the third shaftor interconnecting member 46 with the tenth shaft or interconnectingmember 62. The second brake 36 connects the fifth shaft orinterconnecting member 52 with the stationary element or thetransmission housing 50 in order to restrict the member 52 from rotatingrelative to the transmission housing 50. Likewise, the ten forwardratios are achieved through different combinations of clutch and brakeengagement, as shown in FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches not specifically referenced in a given gear state areinactive or disengaged and, second of all, that during gear shifts,i.e., changes of gear state, between at least adjacent gear states, aclutch engaged or activated in both gear states will remain engaged oractivated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; atransmission housing; first, second, third and fourth planetary gearsets each having first, second and third members; a firstinterconnecting member continuously interconnecting the third member ofthe first planetary gear set with the third member of the thirdplanetary gear set; a second interconnecting member continuouslyinterconnecting the second member of the first planetary gear set withthe third member of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the first member ofthe second planetary gear set with the first member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe second member of the fourth planetary gear set; and six torquetransmitting mechanisms each selectively engageable to interconnect oneof the first, second, and third members with another one of the firstmembers, second members, third members and the transmission housing, andwherein a first of the six torque transmitting mechanisms is selectivelyengageable to interconnect the second member of the first planetary gearset with the third member of the fourth planetary gear set, a second ofthe six torque transmitting mechanisms is selectively engageable tointerconnect the first member of the fourth planetary gear set with thethird member of the fourth planetary gear set, and the torquetransmitting mechanisms are selectively engageable in combinations of atleast three to establish at least ten forward speed ratios and at leastone reverse speed ratio between the input member and the output member.2. The transmission of claim 1 wherein a third of the six torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the first member of the second planetary gear set and thefirst member of the third planetary gear set with the first member ofthe fourth planetary gear set.
 3. The transmission of claim 2 wherein afourth of the six torque transmitting mechanisms is selectivelyengageable to interconnect the first member of the first planetary gearset with the first member of the fourth planetary gear set.
 4. Thetransmission of claim 3 wherein a fifth of the six torque transmittingmechanisms is selectively engageable to interconnect at least one of thethird member of the first planetary gear set and the third member of thethird planetary gear set with the transmission housing.
 5. Thetransmission of claim 4 wherein a sixth of the six torque transmittingmechanisms is selectively engageable to interconnect at least one of thesecond member of the first planetary gear set and the third member ofthe second planetary gear set with the transmission housing.
 6. Thetransmission of claim 1 wherein the third member of the first, third andfourth planetary gear sets and the first member of second planetary gearset are sun gears, the second member of the first, second, third andfourth planetary gear sets are carrier members and the first member ofthe first, third and fourth planetary gear sets and third member ofsecond planetary gear set are ring gears.
 7. The transmission of claim 1wherein the input member is continuously interconnected with at leastone of the second member of the third planetary gear set and the secondmember of the fourth planetary gear set and wherein the output member iscontinuously interconnected the second member of the second planetarygear set.
 8. The transmission of claim 1 wherein two of the torquetransmitting mechanisms are brakes and four of the torque transmittingmechanisms are clutches.
 9. A transmission comprising: an input member;an output member; first, second, third and fourth planetary gear setseach having first, second and third members, wherein the input member iscontinuously interconnected with at least one of the second member ofthe third planetary gear set and the second member of the fourthplanetary gear set and wherein the output member is continuouslyinterconnected the second member of the second planetary gear set; afirst interconnecting member continuously interconnecting the thirdmember of the first planetary gear set with the third member of thethird planetary gear set; a second interconnecting member continuouslyinterconnecting the second member of the first planetary gear set withthe third member of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the first member ofthe second planetary gear set with the first member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe second member of the fourth planetary gear set; and a first torquetransmitting mechanism selectively engageable to interconnect the secondmember of the first planetary gear set with the third member of thefourth planetary gear set; a second torque transmitting mechanismselectively engageable to interconnect the first member of the fourthplanetary gear set with the third member of the fourth planetary gearset; a third torque transmitting mechanism selectively engageable tointerconnect at least one of the first member of the second planetarygear set and the first member of the third planetary gear set with thefirst member of the fourth planetary gear set; a fourth torquetransmitting mechanism selectively engageable to interconnect the firstmember of the first planetary gear set with the first member of thefourth planetary gear set; a fifth torque transmitting mechanismselectively engageable to interconnect at least one of the third memberof the first planetary gear set and the third member of the thirdplanetary gear set with the stationary member; and a sixth torquetransmitting mechanism selectively engageable to interconnect at leastone of the second member of the first planetary gear set and the thirdmember of the second planetary gear set with the stationary member, andwherein the torque transmitting mechanisms are selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 10. The transmission of claim 9 wherein the thirdmember of the first, third and fourth planetary gear sets and the firstmember of second planetary gear set are sun gears, the second member ofthe first, second, third and fourth planetary gear sets are carriermembers and the first member of the first, third and fourth planetarygear sets and third member of second planetary gear set are ring gears.11. The transmission of claim 9 wherein the stationary member is atransmission housing.
 12. A transmission comprising: an input member; anoutput member; first, second, third and fourth planetary gear sets eachhaving a sun gear, a carrier member and a ring gear, wherein the inputmember is continuously interconnected with at least one of the carriermember of the third planetary gear set and the carrier member of thefourth planetary gear set and wherein the output member is continuouslyinterconnected the carrier member of the second planetary gear set; afirst interconnecting member continuously interconnecting the sun gearof the first planetary gear set with the sun gear of the third planetarygear set; a second interconnecting member continuously interconnectingthe carrier member of the first planetary gear set with the ring gear ofthe second planetary gear set; a third interconnecting membercontinuously interconnecting the sun gear of the second planetary gearset with the ring gear of the third planetary gear set; a fourthinterconnecting member continuously interconnecting the carrier memberof the third planetary gear set with the carrier member of the fourthplanetary gear set; and a first torque transmitting mechanismselectively engageable to interconnect the carrier member of the firstplanetary gear set with the sun gear of the fourth planetary gear set; asecond torque transmitting mechanism selectively engageable tointerconnect the ring gear of the fourth planetary gear set with the sungear of the fourth planetary gear set; a third torque transmittingmechanism selectively engageable to interconnect at least one of the sungear of the second planetary gear set and the ring gear of the thirdplanetary gear set with the ring gear of the fourth planetary gear set;a fourth torque transmitting mechanism selectively engageable tointerconnect the ring gear of the first planetary gear set with the ringgear of the fourth planetary gear set; a fifth torque transmittingmechanism selectively engageable to interconnect at least one of the sungear of the first planetary gear set and the sun gear of the thirdplanetary gear set with the stationary member; and a sixth torquetransmitting mechanism selectively engageable to interconnect at leastone of the carrier member of the first planetary gear set and the ringgear member of the second planetary gear set with the stationary member,and wherein the torque transmitting mechanisms are selectivelyengageable in combinations of at least three to establish at least tenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 13. The transmission of claim 12wherein the stationary member is a transmission housing.